Atkinson wrote to The Times, saying: “As a lifelong beneficiary of the freedom to make jokes about religion, I do think that Boris Johnson’s joke about wearers of the burka resembling letterboxes is a pretty good one.

Mr Johnson was reacting to news the first person had been fined for wearing a full-face veil in public in Denmark, and used his Daily Telegraph article to warn against a similar “heavy-handed” movement in the UK.

The row over his comments has split the Conservatives, with the prime minister and others calling on the ex-foreign secretary to apologise and others demanding he should lose the whip.